Fluorine-containing graft or block polymer

ABSTRACT

The present invention provides a graft or a block polymer in which a fluorine rubber and a silicone rubber are chemically bonded. The present invention is a graft or a block polymer comprising at least one kind of a silicone rubber segment and at least one kind of a fluorine elastomer segment. Furthermore, it is preferable that a fluoirne containing elastomer segment is an elastomer segment comprising vinylidene fluoride or an elastomer segment comprising tetrafluoroethylene and that a silicone rubber segment has a unit of dimethylsiloxane and/or methyl-3,3,3-trifluoropropylsiloxane.

TECHNICAL FIELD

The present invention relates to a graft or a block polymer comprisingat least one silicone rubber segment and at least one fluorinecontaining elastomer segment, and a curable composition comprising thepolymer and a vulcanizing agent.

BACKGROUND ART

Both a silicone rubber and a fluorine rubber are rubbers having oilresistance and heat resistance, and these rubbers have been widelyemployed in various fields. The silicone rubber is excellent in lowtemperature resistance, a low degree of hardness, and amine resistance,which are properties which is difficult for the fluorine rubber toimprove, and furthermore, with respect to processing, the siliconerubber can be applied to a wide variety of processing such as LIMmolding.

On the other hand, due to excellent chemical resistance, solventresistance and heat resistance, the fluorine rubber shows highreliabilities that the silicone rubber can not obtain and has beenemployed for applications where other materials can not be employed.

Since these two rubbers have a property of supplementing each other, itis expected that a new material is provided if the rubbers can becomposed by blending, alloying and the like, and various composites ofthese two polymers have been studied heretofore.

For example, it is disclosed that a blended material of an iodinecontaining fluorine elastomer and a vinyl group containing siliconerubber are crosslinked by using a peroxide (for example, see JapaneseUnexamined Patent Publication No.55-50051). Also, a method of blending afluorine rubber introduced with a double bond and a silicone rubber andconducting co-crosslinking is disclosed (for example, see JapaneseUnexamined Patent Publication No.06-192524). But excellent propertiescan not be expected since the two polymers are hard to fully dispersefinely and uniformly if two kinds of polymers, which are not compatible,are plainly blended and crosslinked

With respect to technology relating to a block or a graft, an elastomercomposition which is obtained by dissolving a silicone rubbers in Freon113 and graft bonding with VdF/HFP is disclosed (for example, seeJapanese Unexamined Patent Publication No.01-240552). But excellentproperties can not be expected since a reactive site for the graft isnot uniform.

Also, a graft copolymer using tetrafluoroethylene/propylene copolymerfor a fluorine rubber is disclosed (for example, see Japanese UnexaminedPatent Publication No.56-28219). But, an excellent vulcanizing propertycan not be expected since a curing site is an epoxy group, an aminogroup, an organic acid group or a vinyl group.

Furthermore, a vulcanizing rubber composition in which compatibility ofa fluorine rubber and an organopolysiloxane is improved by using anorganosiloxane having a particular functional group is disclosed (forexample, see Japanese Unexamined Patent Publication No.04-180930).Although organosiloxane improves compatibility of a fluorine rubberpolymer and a silicone, sufficient compatibility can not be expectedsince the organosiloxane does not contain a component of a fluorinerubber.

The present invention provides a graft or a block polymer in which afluorine rubber and a silicone rubber are chemically bonded.

DISCLOSURE OF INVENTION

Namely, the present invention relates to a graft or a block polymercomprising at least one kind of a silicone rubber segment and at leastone kind of a fluorine containing elastomer segment.

The fluorine containing elastomer segment is preferably an elastomersegment comprising vinyliden fluoride or an elastomer segment comprisingtetrafluoroethylene.

The silicone rubber segment preferably has a dimethylsiloxane unitand/or a methyl-3,3,3-trifluoropropylsiloxane unit.

The graft or the block polymer is preferably obtained by reacting afluorine containing compound with a silicone rubber having at least oenamino group, wherein the fluorine containing compound is obtained bypolymerizing a fluorine containing monomer with the fluorine compoundthe formula (1):

-   -   (wherein X¹ is an iodine atom or a bromine atom, R_(f) ¹ is a        bivalent alkylene group having 1 to 30 carbon atoms, which can        contain an oxygen atom, and R₁ is an alkyl group having 1 to 3        carbon atoms.)

Also, the present invention relates to a curable composition comprisingthe above mentioned polymer and a vulcanizing agent.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to a graft or a block polymer comprisingat least one silicone rubber segment and at least one fluorinecontaining elastomer segment.

Since the graft or the block polymer of this present invention containsat least one kind of a fluorine containing elastomer segment, thepolymer can give a property of a fluorine rubber such as excellentsolvent resistance to a curable composition, and the polymer serves as acompatibilizer, which helps micro dispersion effectively in a blend of afluorine rubber and a silicone rubber.

Examples of processes of preparing the graft or the block polymercomprising at least one silicone rubber segment and at least onefluorine containing elastomer segment are:

(A) a process of polymerizing a fluorine containing compound having ahalogen atom at the end of the polymer with at least one kind of amonomer by halogen transfer polymerization and bonding the obtainedfluorine containing elastomer and a silicone rubber.

(B) a process of polymerizing a silicone rubber having a halogen atom atthe end of the polymer with at least one kind of a monomer by halogentransfer polymerization. The process is not limited thereto.

An example of a process(A) is a process of preparing the graft or theblock polymer is a process of reacting a fluorine containing compoundhaving a fluorine containing elastomer segment, which is obtained bypolymerizing (halogen transfer polymerization) a fluorine containingcompound represented by the following formulas (1):

-   -   (wherein X¹ is an iodine atom or a bromine atom, R_(f) ¹ is a        bivalent alkylene group having 1 to 30 carbon atoms, which can        contain an oxygen atom, and R1 is an alkyl group having 1 to 3        carbon atoms),    -   or preferably the following formula (2):        (wherein R_(f) ² to R_(f) ⁴ may be the same or different        respectively and are bivalent fluorine containing alkylene        groups, X¹ is an iodine atom or a bromine atom, R² is an alkyl        group having 1 to 3 carbon atoms, and n is an integer of 0 to        20),    -   with at least one kind of monomer,    -   with a silicone rubber having at least one amino group.

R_(f) ¹ is a bivalent alkylene group having 1 to 30 carbon atoms, whichcan contain an oxygen atom, examples thereof are:—R_(f) ²—O—(—R_(f) ³O—)—_(n)R_(f) ⁴—

-   -   (n and R_(f) ²˜R_(f) ⁴ are the same as above mentioned), —(CF₂        CF₂ )_(m)—, —(CH₂CF₂CF₂O)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)—,        —(CH₂CF₂CF₂O)₁CH₂CF₂—, —(CF₂)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)—,        —(CH₂CF₂CF₂O)₁(CF₂CF₂O)_(m)CF₂—,        —(CF₂CF₂CF₂O)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)—,        CH₂CF₂CF₂O(CH₂CF₂CF₂O)_(n)CH₂CF₂-(m, 1 are integers of at least        0), —CF₂—, —CF₂CF₂—, —CH₂CF₂CF₂—, —CF₂CF₂CF₂—, —CF(CF₃)—,        —CF(CF₃)CF₂—.

R_(f) ² to R_(f) ⁴ are bivalent fluorine containing alkylene groups,preferably a fluorine containing alkylene group having 1 to 5 carbonatoms, and more preferably a fluorine containing alkylene group having 2to 3 carbon atoms.

Examples of R_(f) ², R_(f) ³, and R_(f) ⁴ are —CF₂, CF₂CF₂—,—CH₂CF₂CF₂—, —CF₂CF₂CF₂—, —CF(CF₃)—, —CF(CF₃)CF₂—. Among those, R_(f) ²is preferably —CF₂—, —CF₂CF₂—, —CH₂CF₂CF₂—, —CF₂CF₂CF₂— in viewpoint ofeasiness of co polymerization of a fluorine rubber component. R_(f) ³ ispreferably —CF₂—, —CF₂CF₂—, —CH₂CF₂CF₂—, —CF(CF₃)CF₂— in viewpoint ofeasiness of synthesis, and R_(f) ⁴ is preferably —CF(CF₃)—, —CH₂CF₂—,—CF₂CF₂— in viewpoint of easiness of synthesis.

Also, formula (5) represented by the following formula:—R_(f) ²—O—(—R_(f) ³O—)—_(n)R_(f) ⁴—

is preferably —CH₂CF₂CF₂O(CH₂CF₂CF₂O)_(n)CH₂CF₂—,—CH₂CF₂CF₂O(CF(CF₃)CF₂O)_(n)CF(CF₃)-(n is an integer of 0 to 20).

n is an integer of 0 to 20, preferably 0 to 10, and more preferably 0 to5. When n is more than 10, a compound which does not have halogen tendsto generate at synthesis as an impurity.

X¹ is preferably an iodine atom or a bromine atom since it is employedin a crosslinking reaction later, but particularly preferably an iodineatom in viewpoint of high reactivity.

Examples of R¹ and R² are a methyl group, an ethyl group and a propylgroup, and among those, a methyl group is preferable in view point ofeasiness of synthesis and high reactivity to amine.

Examples of a compound represented by the formula (1) or the formula (2)are X¹—(CH₂CF₂CF₂O)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)COOCH₃, X¹—(CH₂CF₂CF₂O),CH₂CF₂COOCH₃, X¹—(CF₂)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)COOCH₃,X¹—(CH₂CF₂CF₂O)₁(CF₂CF₂O)_(m)CF₂COOCH₃,X¹—(CF₂CF₂CF₂O)₁(CF(CF₃)CF₂O)_(m)CF(CF₃)COOCH₃(X¹ is the same as abovementioned, m and 1 are integers that are not less than 0),

-   -   and more specifically,    -   I(CF₂CF₂)_(n)COOCH₃, ICH₂CF₂COOCH₃,        ICH₂CF₂CF₂O(CH₂CF₂CF₂O)_(n)(CF(CF₃)CF₂O)_(m)CF(CF₃)COOCH₃,        ICH₂CF₂CF₂O(CH₂CF₂CF₂O)_(n)CH₂CF₂COOCH₃,        ICH₂CF₂CF₂O(CF(CF₃)CF₂O)_(n)CF(CF₃)COOCH₃ (wherein both m and n        are integers of 0 to 20).

Though there is no particular limitation, a silicone rubber containingat least one amino group is preferably represented by the followingformula:(R³HN)_(n)Y¹   (3)

-   -   (wherein Y¹ is a silicone rubber, R³ is a hydrogen or an alkyl        group having 1 to 3 carbon atoms, a phenyl group or its        substituent, and n is an integer of at least one).

Examples of R³ are a hydrogen atom, a methyl group, an ethyl group, apropyl group, and a phenyl group, and among those, a hydrogen atom and amethyl group are preferable in viewpoint of reactivity and chemicalstability of amido bonding.

As a silicone rubber, a silicone rubber represented by the followingformula:

-   -   (wherein R⁴ to R¹¹ may be the same or different respectively and        are a hydrogen, an alkyl group having 1 to carbon atoms, an        alkenyl group, a saturated or unsaturated fluorohydrocarbon        group, a phenyl group or its substituent, a is 0 to 3000, and b        is 0 to 3000, 10≦a+b≦3000) is preferable

Also, a respective repeating unit represented as (R⁶R⁷SiO) and (R⁸R⁹SiO)in the formula (4) is a dimethylsiloxane unit or amethyl-3,3,3-trifluoropropylsiloxane unit represented by the followingformula:

is preferable in viewpoint of heat resistance and chemical resistance ofthe obtained crosslinked product.

Also, (R⁶R⁷SiO) and (R⁸R⁹SiO) may be a silicone rubber segment in whicheach block segment is bonded, a silicone rubber segment in which both ofthem are bonded randomly, and a silicone rubber segment comprising oneof the repeated units.

Examples of an alkyl group having 1 to 5 carbon atoms are a methylgroup, an ethyl group, a butyl group, examples of an alkenyl group are avinyl group, and an allyl group, and examples of a saturated or anunsaturated fluorohydrocarbon group are —CH₂CH₂CF₃, —CH₂CH₂CF₂CF₃,—CH₂CH₂CF₂CF₂CF₃, —CH₂CH₂CF₂CF₂CH═CH₂, but among those, —CH₂CH₂CF₃— ispreferable in viewpoint of easiness of synthesis.

In the formula, a is preferably 0 to 3000 and more preferably 10 to2000.

In the formula, b is preferably 0 to 3000 and more preferably 0 to 2000.

Furthermore, a and b preferably satisfy 10≦a+≦3000, more preferablysatisfy 10≦a+≦s2000. When a+b is less than 10, properties as a siliconerubber do not tend to appear, and when it is more than 3000, handlingtends to become difficult due to high molecular weight.

As an example of a process(B), the graft or the block polymer comprisingat least one kind of a silicone rubber segment and at least one kind ofa fluorine containing elastomer segment can be obtained by polymerizing(halogen transfer polymerization) at least one kind of monomers with acompound represented by the following formula (5):

-   -   (wherein X¹, R_(f) ¹, and Y¹ are the same as mentioned above),        or a compound represented by the following formula (6):    -   (wherein X¹, R_(f) ² to R_(f) ⁴, and Y¹ are the same as        mentioned above), which are obtained by a reaction of amide        formation of a halogen containing compound represented by the        formula (1) or (2) with an amino group containing compound        represented by the formula (3).

Weight average molecular weight of a fluorine containing compoundrepresented by Formula (5) or (6) is preferably 500 to 500000, and morepreferably 1000 to 200000.

Since halogen groups are placed at both ends of the fluorine containingcompound represented by the formula (5) or (6), the fluorine containingcompound can cure the compound itself and co-vulcanize in blending witha fluorine rubber, and a curable composition having a balanced propertycan be obtained.

There is not particular limitation for a process of a reaction of amidoformation in the process (A) and (B), processes commonly employed can beemployed.

Between the process (A) and (B), the process (A) is more advantageous inviewpoint of chain transferability.

Also, a process of halogen transferability in the process (A) and (B) isexplained below.

Carbon-halogen bonding is a relatively weak bonding and cleaves asradical in the presence of radical generator. Since reactivity of thegenerated radical is high, a monomer reacts by addition propagation,thereafter, the reaction stops by drawing out a halogen atom from ahalogen compound.

As a process of halogen transfer polymerization, publicly knownprocesses such as bulk polymerization, solution polymerization,suspension polymerization and emulsion polymerization can be adopted.When a process of emulsion polymerization is adopted, examples are aprocess of seed polymerization described in International Publication No00/01741 pamphlet and a process of micro emulsion described in JapaneseUnexamined Patent Publication No 63-8406 and No62-288609, but are notlimited thereto.

In case of conducting halogen transfer polymerization withemulsification polymerization, the emulsion polymerization is conductedby dispersing a compound having a halogen atom at the end of thecompound into water with an emulsifier (a part of liquid phase),pressuring with monomer gas which has the same composition as the aimedfluorine containing elastomer segment after replacing a part of gasphase with nitrogen and the like, and polymerizing.

A reaction vessel is composed of this liquid phase and the gas phasecomprising monomer gas and polymerization is initiated by injectingpolymerization initiator in the reaction vessel. In the course ofcontinuing polymerization, monomers are consumed and added monomers arecontinued to be supplied since a concentration of the monomer becomeslower in the reaction vessel. Although the amount of the added monomerdepends on the composition of the added monomer and an aimed polymer, anamount that keeps a composition of a monomer constant in the reactionvessel at the beginning of polymerization is preferable.

There is no particular limitation for pressure and suitable pressure isadopted.

Furthermore, mixing a part of liquid phase is preferable. As a mean ofmixing, an anchor blade, a turbine blade, a slide blade and the like canbe employed, but mixing by a great blade called full-zone or max-blendis preferable in viewpoint of diffusion of monomers and excellentdispersion stability of a polymer. As a mixing device, both a horizontalmixing device and a vertical mixing device can be employed.

There is no particular limitation for a polymerization temperature, andthe suitable temperature is adopted according to a kind of apolymerization initiator. But if the temperature becomes too high, chaintransfer reaction toward a polymer main chain and unstability of aniodine group and the like occur easily, it is possible that the aimedpolymer can not be obtained. The temperature is preferably 5 to 120° C.and more preferably 10 to 90° C.

A monomer which forms a fluorine containing elastomer segment by halogentransfer polymerization contains at least one kind of fluoro-olefin, andits comonomer may contain an ethylencally unsaturated compound exceptfor fluoro-olefin.

As a fluoro-olefin employed in the present invention, a fluoro-olefinrepresented by the formula CX²X³═CX⁴X⁵ is preferable. In the formula, X²to X⁴ are a hydrogen atom or a halogen atom, X⁵ is a hydrogen atom, ahalogen atom, a carboxyl group, an alkyl group having 1 to 9 carbonatoms in which a part or all of hydrogen are replaced with fluorineatoms, and an alkoxyl group in which a part or all of hydrogen arereplaced with fluorine atoms,

-   -   and the olefin contains at least one fluorine atom.

As the fluoro-olefin represented by the following formula CX²X³═CX⁴X⁵,examples are hexafluoropropylene (HFP), vinylidenfluroride (VdF),tetrafluoroethylene (TFE), trifluoroethylene, pentafluoropropylene,vinylfluroride, hexafluoroisobutene, chlorotrifluoroethylene (CTFE),trifluoropropylene, tetrafluoropropylene, and perfluoro (alkyl vinylether) (PAVE).

Examples of the above mentioned perfluoro (alkyl vinyl ether) areperfluoro (methyl vinyl ether) (PMVE), perfluoro (ethyl vinyl ether)(PEVE), and perfluoro (propyl vinyl ether) (PPVE).

Also, examples of the fluoro-olefin except for CX²X³═CX⁴X⁵ arepolyfluorodienes sich as CF₂═CFOCF₂CF═CF₂, CF₂═CFCF=CF₂, andCF₂═CFCF₂OCF═CF₂,

-   -   a fluoro-olefin containing a functional group represented by the        following formula:    -   (wherein Y² is —CH₂I, —OH, —COOH, —SO₂F, —SO₃M (M is hydrogen, a        NH₄ group or an alkali metal), a carboxylate, a carboxyester        group, an epoxy group, a cyano group, and an iodine atom, X⁶ and        X⁷ are the same or different and both of them are hydrogen atoms        or fluorine atoms, and R_(f) ⁵ is a bivalent fluorine containing        alkylene group having 0 to 40 carbon atoms and may contain an        ether bonded oxygen atom), or the compound represented by the        following formula:

Fluoro-orefin containing a functional group is preferable as afunctionality monomer for surface reforming and increasing acrosslinking density, and polyflorodienes are preferable in viewpoint ofefficiency of crosslinking.

Examples of the fluoro-olefin containing a functional group arecompounds represented by the following formulas:

-   -   and compounds represented by the following formulas (13):

Also, a monomer represented by the formula, CF₂═CFOCF₂CF₂CH₂I, which isdisclosed in Japanese Unexamined Patent Publication No.62-12734 as afluoro-olefin containing a functional group, is preferable for thepurpose of increasing density of crosslinking.

Examples of the ethylenically unsaturated compound except forfluoro-olefin are an a-olefin monomer having 2 to 10 carbon atoms suchas ethylene(ET), propylene, butene, and pentene, and alkyl vinyl ether,having 1 to 20 carbon atoms of an alkyl group, such as methyl vinylether, ethyl vinyl ether, propyl vinyl ether, cychlohexyl vinyl ether,hydroxybutyl vinyl ether, and butyl vinyl ether, but the compound is notparticularly limited thereto.

A combination of monomers forming the fluorine containing elastomersegment of the polymer of the present invention is preferably at leastone kind of fluoro-olefin represented by the formula CX²X³═CX⁴X⁵ inviewpoint of a property of a cured product crosslinke the obtainedcuring the obtained polymer.

A fluorine containing elastomer segment of the polymer of the presentinvention is preferably an elastomer comprising VdF or an elastomercomprising TFE, and more preferably VdF/HFP, VdF/TFE/HFP, VdF/TFE/PMVEor TFE/PMVE in viewpoint of heat resistance and chemical resistance.

Weight average molecular weight of the graft or the block polymer of thepresent invention obtained by halogen transfer polymerization ispreferably 1000 to 500000, more preferably 2000 to 200000. When weightaverage molecular weight is less than 1000, curing does not tend toprogress sufficiently. When it is more than 500000, the polymer does nottend to be processed due to a high viscosity.

Molecular weight distribution (weight average molecular weight Mw/numberaverage molecular weight Mn) is preferably 1 to 8. When molecular weightdistribution is more than 8, it is possible that properties become lowsince differences of molecular weight of a fluorine rubber segment and asilicone rubber segment is large.

Also, the weight ratio of a silicone rubber segment and a fluorinecontaining elastomer segment is preferably 1/99 to 99/1, and morepreferably 10/90 to 90/10. When the ratio of the silicone rubber segmentis less than 1/99, the polymer hardly show properties of a siliconerubber and does not tend to reveal effects in case of using as acompatibilizer. When the ratio is more than 99/1, improving a propertyby introducing a fluorine rubber can not be expected.

Also, a content of a halogen atom in the polymer of the presentinvention obtained by halogen transfer polymerization is preferably 0.1to 10% by weight, and more preferably 0.2 to 8% by weight. When thecontent rate of a halogen atom is less than 0.1% by weight,vulcanization is not sufficient at vulcanizing and a compressionpermanent strain tends to be lowered, and when the rate is more than 10weight %, crosslinking density is too high and efficiency as a rubbertends to be degraded, such as too small elongation.

As a polymerization initiator used in halogen transfer polymerization,an oil soluble radical polymerization initiator or a water solubleradical initiator can be used.

As an oil soluble radical polymerization initiator used in the presentinvention, a commonly known oil soluble peroxide is used andrepresentative examples are dialkylperoxy carbonates such asdiisopropylperoxy dicarbonate and di-sec-butylperoxy dicarbonate, peroxyesters such as t-butyl, peroxyisobutylate and t-butylperoxypivarate anddialkyl peroxides such as di-t-butyl peroxide, and also di[perfluoro(orfluorochloro)acyl]peroxides such asdi(ω-hydro-dodecafluoroheptanoyl)peroxide,di(ω-hydro-tetradecafluorooctanoyl)peroxide,di(ω-hydro-hexadecafluorononanoyl)peroxide,di(perfluorobutyryl)peroxide, di(perfluorovaleryl)peroxide,di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide,di(perfluorooctanoyl)peroxide, di(perfluorononanoyl) peroxide,di(ω-chloro-hexafluorobutyryl) peroxide,di(ω-chloro-decafluorohexanoyl)peroxide,di((ω-chloro-tetradecafluorooctanoyl)peroxide,(ω-hydro-dodecafluoroheptanoyl-(ω-hydrohexadecafluorononanoyl-peroxide,ω-chloro-hexafluorobutyl-ω-chloro-decafiluorohexanoyl-peroxide,ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide,di(dichloropentafluorobutanoyl)peroxide,di(trichlorooctafluorohexanoyl)peroxide,di(tetrachloroundecafluorooctanoyl)peroxide,di(pentachlorotetradecafluorodecanoyl)peroxide, anddi(undecachlorodotriacontafluorodocosanoyl)peroxide.

However, a soluble radical polymerization initiator is preferably usedsince peroxycarbonates such as diisopropyl peroxycarbonate (IPP) anddi-n-propylperoxicarbonate (NPP) which are typical oil solubleinitiators, have a risk of explosion, are expensive, and they have aproblem that scales on the wall in the polymerization vessel aregenerated easily during a polymerization reaction.

As an water soluble radical polymerization initiator, a commonly knownwater soluble peroxide is usually used and examples are ammonium salts,potassium salt, and sodium salt such as persulfaric acid, perboric acid,perchloric acid, perphosphoric acid, and percarbonic acid,t-butylpermalate, and t-butylhydroperoxide.

An amount of a water soluble radical initiator is more than an amount(for example, several ppm against water concentration) which does notdiminish the polymerization speed remarkably, and the amount is addedall at once at the beginning of polymerization, or added successively,or continuously, but is not particularly limited thereto. The higherlimit is within a range which can remove polymerization reaction heatfrom the surface of the device.

In the preparing process of the present invention, an emulsifier, amolecular weight regulator, a pH regulator and the like can be added.The molecular weight regulator can be added at once in the beginning oradded continuously or separately.

As the emulsifier, a nonionic surfactant, an anionic surfactant, acationic surface-active agent and the like can be used, and particularlyfluorochemical anionic surfactant such as perfluorooctanoic acidammonium is preferable. An amount (against polymer water) is preferably50 to 5000 ppm.

Examples of a molecular weight regulator are isopentane, isopropanol,acetone, various mercaptan, carbon tetrachloride, cyclohexane,monoiodomethane, 1-iodoethane, 1-iodo-n-propane, isopropyl iodide,diiodomethane, 1,2-diiodoethane, and 1,3-diiodo-n-propane, Other thanesters such as malonic acid dimethyl, malonic acid diethyl, acetic acidmethyl, acetic acid ethyl, acetic acid butyl, and succinic acid dimetylbut are not preferably used to the utmost since a blockade ratio by afunctional group such as a halogen group and alkylester group at the endof the polymer becomes low.

Other then the above, buffers and the like can be added suitably, butthe amount is within the range which does not lose efficiency of thepresent invention.

The polymer of the present invention obtained by halogen transferpolymerization can be vulcanized effectively, since it has halogengroups at the end of the main chain and/or the side chain and thehalogen at the end becomes an effective curing point.

Also, a functional group can be introduced at the end of the main chainand/or the side chain by reacting the above mentioned polymer havinghalogen groups at the end of the main chain and/or the side chain ,whichis obtained by halogen transfer polymerization, with thiol metalrepresented by the formula (8):M-S—R¹²—(X⁸)_(m)   (8)

-   -   (wherein X⁸ is the same or different, and —OH or a hydrocarbon        group having 2 to 10 carbon atoms and at least one unsaturated        bond, R¹² is an organic group of at least two valence or a        direct bond, M is alkali metal, and m is an integer of 1 to 3.)

R¹² is an organic group of at least two valence or a direct bond, andexamples of an organic group of at least two valence are an alkylenegroup having 1 to 10 carbon atoms such as a methylene group, an ethylenegroup, and a propylene group,

-   -   an aromatic hydrocarbon group having 6 to 20 carbon atoms such        as a phenylene group and a naphthilene group,    -   and an aralkylene group such as —C₆H₄CH₂—.

M is an alkali metal such as litium (Li), sodium (Na), or potassium (K).

Also, as conditions for a reaction, appropriate conditions can beselected suitably by a fluorine containing elastomer, thiol metal, and akind of a solvent, but are not limited thereto.

The curing composition of the present invention comprises the abovementioned polymer obtained by halogen transfer polymerization and/or apolymer introduced with a functional group, which is obtained byreacting the polymer with thiol metal represented by the formula (8),and a vulcanizing agent.

A vulcanizing agent possibly used in the present invention can beselected by an adopted vulcanizing system suitably. As the vulcanizingsystem, a polyamine vulcanizing system, a polyol vulcanizing system anda peroxide vulcanizing system can be used, but particularly whenvulcanizing by a peroxide vulcanizing system, effects of the presentinvention are revealed remarkably.

As a vulcanizing agent, an example of a polyol vulcanizing system is apolyhydroxy compound such as bisphenol AF, hydroquinone, bisphenol A, ordiaminobisphenol AF, an example of a peroxide vulcanizing system is anorganic peroxide such as α,α′-[bis(t-butylperoxy)diisopropyl]benzene, 2,5-dimethyle-2,5-di(t-butylperoxy)hexane, or dicumylperoxide, and anexample of a polyamine vulcanizing system is a polyamine compound suchas hexamethylenediaminecarbamate, andN,N′-dicinnamyliden-1,6-hexamethylenediamine, but are not limitedthereto.

Among those, 2,5-dimethyle-2,5-di(t-butylperoxy)hexane is preferable inviewpoint of vulcanization and handling.

An amount of a vulcanizing agent is 0.01 to 10 parts by weight,preferably 0.1 to 5 parts by weight, based on 100 parts by weight of thegraft or the block polymer. When the amount of the vulcanizing agent isless than 0.01 part by weight, a property of a shaped article tends tobe lowered since a degree of vulcanization is in short, and when theamount of the vulcanizing agent is more than 10 parts by weight, and theamount tends not to be economically preferable as well as the longvulcanizing time due to the high vulcanizing density.

As a vulcanizing assistant of a polyol vulcanizing system, organic saltcommonly used for vulcanizing an elastomer such as various quarterlyammonium salts, quarternary phosphonium salt, cyclic amine, or onefunctional amine compound can be employed. Concrete examples arequarternary ammonium salt such as tetrabutylammonium bromide,tetrabutylammonium chloride, benzyltributylammonium chloride,benzyltriethylammonium chloride, tetrabutylammonium hydrogen sulfate, ortetrabutylammonium hydroxide, quarterly phosphonium salt such asbenziltriphenylphosphonium chloride, tributylallylphosphonium chloride,tributyl-2-methoxypropylphosphonium chloride, orbenzylphenyl(dimethylamino)phosphonium chloride, one functional aminesuch as benzylmethyanolamine or benzylethanolamine, and cyclic aminesuch as 1,8-diazabicyclo[5.4.0]-undeca-7-en.

Examples of a vulcanizing assistant are triallylcyanurate,triallylisocyanurate(TAIC), tris(diallylamine-s-triazine),triallylphosphite, N,N-diallylacrylamide, hexaallylphosphoramide,N,N,N′,N′-tetraallyltetraphthlamide, N,N,N′,N′-tetraallylmaronamide,trivinylisocyanurate, and 2,4,6-trivinylmethyltrisiloxane,tri(5-norbornene-2-methyne)cynurate. Among those,triallylisocyanurate(TAIC) is preferable in viewpoint of vulcanizationand properties of vulcanizate.

An amount of the vulcanizing assistant is 0.01 to 10 parts by weightbased on 100 parts by weight of the graft or the block polymer, andpreferably 0.1 to 5.0 part by weight. When the vulcanizing assistantagent is less than 0.01 part by weight, vulcanizing time tends to becomelong enough not to stand for practical use, and when the vulcanizingassistant agent is more than 10 parts by weight, compression permanentstrain tends to become low as well as too short vulcanizing time.

Also, a compound having at least two Si—H groups in one molecule ispreferable in the viewpoint of an ability to form a three dimentionalmesh structure by hydrosilylic reaction in case of a polymer introducedwith a hydrocarbon group having at least one unsaturated bond and 2 to10 carbon atoms as a functional group, according to a thiol metalrepresented by the formula (8), as a vulcanizing agent.

Also, in case of a hydrosilylic reaction of a compound having at leasttwo Si—H groups in one molecule with a polymer introduced with ahydrocarbon group having at least one unsaturated bond and 2 to 10carbon atoms as a functional group, according to a thiol metalrepresented by the formula (8), a catalyst for hydrosilylic reactionsuch as an addition reaction catalyst (a 8th group metallic compoundsuch as) comprising elements of the platinum group such as a catalyst ofthe platinum series, palladium series, and rhodium series and/or areaction inhibitor is used preferably.

In case of the polymer introduced with -OH group as a functional group,according to the thiol metal represented by the formula (8), acidanhydride is preferably used as a vulcanizing agent. Examples of acidanhydrate are pyromellitic acid anhydrate, tetrahydrofrantetracarboxylicacid anhydride, and benzophenonetetracarboxylic acid anhydride, examplesof a polyamine compound are polyamine such as hexamethylenediamine,triethylenetetramine, or triethylenediamine, and examples of apolyisocyanate compound are tolylendiisocyanate,diphenylmethanediisocyanate, and hexamethylenediidocyanate. The abovementioned polyisocyanate compound can be a block form which can select apre-polymer and the crosslinking temperature. Examples of the curingagent are polycarboxylic acid such as adipic acid, andalkoxymethylmelamine such as methoxymethylmelamine.

In case that the polymer of the present invention has an —OH group andis also an fluorine containing elastomer in vinylidene series, thepolyol crosslinking system can be used preferably.

Furthermore, a filler, a processing aid, carbon black, an inorganicfiller, metal oxide such as magnesium oxide, and metal hydroxide such ascalcium hydroxide, which are common additive, can be used for thepresent invention, as long as the purpose of the present invention isnot impaired.

There is no particular limitation for a process of adjusting andvulcanizing the composition, and conventional processes publicly knownsuch as compression molding, extrusion molding, transfer molding, andemission molding can be adopted.

Tensile elongation at break (Eb) of a shaped form of a vulcanizedfluorine containing elastomer by using a vulcanizing agent is preferably50 to 500%. When the tensile elongation at break is less than 50%, theform does not tend to be suitable for a seal material, losing so-called“properties of a rubber”, and when Eb is more than 500%, compressionpermanent strain (CS) tends to be degraded since crosslinking densitybecomes too low.

Also, compression permanent strain of shaped article after 72 hours at200° C. is preferably 10 to 50%, and more preferably 10 to 30%. When thecompression permanent strain is more than 50%, properties of a sealmaterial tend to be degraded.

Vulcanization conditions at the above mentioned measurement are thestandard amount and the standard vulcanization condition describedbelow:

(Standard amounts) Polymer 100 parts by weight Triallylisocyanurate 4parts by weight Perhexa 25B 1.5 parts by weight Carbon black MT-C 20parts by weight

-   -   (Standard vulcanizing conditions)    -   Kneading process: Roll kneading    -   Press vulcanization: 10 minutes at 160° C.    -   Oven vulcanization: 4 hours at 180° C.

The graft or the block polymer of the present invention having at leastone kind of a silicone rubber segment and at least one kind of afluorine elastomer segment obtained by conducting halogen transferpolymerization can obtain a polymer in which both segments are uniformby chemically bonding both of bad compatible segments. Furthermore, thepolymer is excellent in chemical resistance, low-temperature resistanceand the like.

The polymer obtained by the present invention can give a curablecompound by adding a crosslinking agent to the polymer itself, and isemployed as a compatibilizer which improves compatibility by adding itin blending fluorine and a silicone rubber.

A shaped article of the present invention is employed in fieldsrepresented below.

In the related field of semiconductors such as a semiconductormanufacturing device, a liquid crystal panel manufacturing device, aplasma panel manufacturing device, plasma address liquid crystal panel,a field emission display panel and a substrate of a solar battery,examples are an O (square) ring, a packing, a seal material, a tube, aroll, a coating, a lining, a gasket, a diaphram, and a hose, and thesecan be used for a CVD device, a dry etching equipment, a wet etchingequipment, an oxidization dispersion diffuser, a sputtering equipment,an ashing equipment, a wet scrubber, an ion implanter, an exhauster, achemical fitting, and a gas fitting. Concretely, examples are used as anO-ring and seal material for a gate bulb, an O ring and a seal materialfor a quartz window, an O ring and seal material for a chamber, an Oring and a seal material for a gate, an O ring and a seal material for abell jar, an O ring and a seal material for a coupling, an O ring, aseal material, a diaphragm for a pump, an O ring and seal material for asemiconductor gas regulator, an O ring and seal material of a resistsolution and a pealing solution, a hose and a tube for a wafer washingsolution, a roll for a wafer transport, a lining and a coating for aresist solution vessel and a pealing solution vessel, a lining and acoating for a wafer washing vessel or a lining and a coating for a wetetching vessel. Furthermore, examples are used for a sealant-sealingagent, a coating of quartz for a optical fiber, an electric componentsfor the purpose of insulation, vibration proof, water proof and dampproof, a potting, a coating and an adhesive seal for a circuit board,gasket for magnetic storage, a modifier for a sealant material such asepoxy and a sealant for a clean room-clean facility.

In the field of automobiles, a gasket, a shaft seal, a valve stem seal,a sealing material or a hose can be employed for an engine andperipheral equipment,

-   -   a hose and a sealing material is used for an AT equipment, an O        (square) ring, a tube, a packing, a core material of a valve, a        hose, a sealing material and a diaphragm can be employed for a        fuel system and peripheral equipment. Concretely, examples are        an engine head gasket, a metal gasket, a sump gasket, a crank        shaft seal, a cam shaft seal, a valve stem seal, a manifold        packing, an oil hose, a seal for a fuel pump, an ATF hose, an        injector O ring, an injector packing, a fuel pump O ring, a        diaphragm, a fuel hose, a crank shaft seal, a gear box seal, a        power piston packing, a seal for a cylinder liner, a seal for a        valve stem, a front pump seal of an automatic shaft, a rear        accelerator pinion seal, a gasket of an universal joint, a        pinion seal of a speedometer, a piston cup of a foot brake, an O        ring of torque transmission, an oil seal, an autoexhaust a seal        for a reheating equipment, a bearing seal, an EGR tube, a twin        carb tube, a diaphragm for the sensor of a carburetor, a        vibration-proof rubber (an engine mount, an exhaust out-let), a        hose for an reheating equipment, and an oxygen sensor bush.

In the field of aircraft, rockets and, ships and vessels, examples are adiaphragm, an O (square) ring, a valve, a tube, a packing, a hose, and asealing material, and these can be employed for a fuel system.Concretely, in the field of an aircraft, a jet engine valve stem seal, afueling hose, a gasket and an O ring, a rotating shaft seal, a gasket ofa hydraulic machine, and a seal for a fire resisting wall, and in thefield of ships and vessels, examples are a shaft stern seal for apropel, a valve stem seal for a breather of a diesel engine, a valveseal of a butterfly valve, and a seal for a shaft of a butterfly valve.

In the field of chemical products such as a plant, examples are alining, a valve, a packing, a roll, a hose, a diaphragm, an O (square)ring, a tube, a sealing material, and a chemical resistance coating, andthese can be employed for processes of manufacturing chemicals such asmedicine, agricultural chemicals, and coating, plastic. Concretely,examples are a seal of a pump for chemicals, a flow indicator and apipe, a seal of heat exchanger, a packing for a glass condenser ofsulfuric acid manufacturing equipment, a seal of a spray plane and anagricultural chemicals transport pump, a seal of gas piping, a seal fora plating solution, a packing of a high temperature vacuum dryer, akoroseal of a belt for paper manufacturing, a seal of a fuel battery, ajoint seal of wind channel, a trichlene resistance roll (for fiberdyeing), an acid resistance hose (for concentrated sulfuric acid), apacking of a tube connecting part of gas chromatography and a pH meter,a chloride gas transport hose, a rain water drain hose of a benzene ortoluene storage tank, and a seal, a tube, a diaphragm and a valve of ananalytical equipment and a physical and chemical equipment.

In the field of chemicals such as medical drugs, the shaped article ofthe present invention is employed as a plug for chemicals.

In the field of photography such as a developing equipment, in the fieldof printing such as printing machinery, and in the field of coating suchas coating facility, an example is a roll, and each of them is employedas a roll for a film developing machine-an X-ray film developingmachine, a printing roll and coating roll. Concretely, examples are adeveloping roll of a film developing machine-an X-ray film developingmachine, a gravure roll and a guide roll of a printing roll, a gravureroll of a magnetic tape manufacture coating line of a coating roll, aguide roll of a magnetic tape manufacture coating line, and variouscoating rolls. Furthermore, examples are a seal of a xerography machine,a printing roll, a scraper, a tube and a part of a valve of a printingequipment, a coating roll, a scraper, a tube, and a part of a valve ofcoating facility, an ink tube, a roll and a belt of a printer, a beltand a roll of a xerography machine, and a roll and a belt of a printingmachine.

Also, a tube can be used in the field of analytical-physical andchemical equipment.

In the field of food plants, examples are a lining, a valve, a packing,a roll, a hose, a diaphragm, an O (square) ring, a tube, a seal materialand a belt, and these can be used in a process of manufacturing food.Concretely, examples are used as a seal for a plate heat exchanger and aseal of an electric magnetic valve for a vending machine.

In the field of atomic power plant equipment, examples are a packing, anO ring, a hose, a seal material, a diaphragm, a valve, a roll and atube.

In the field of iron and steel such as an iron plate processingfacility, an example is a roll and is used for a roll for an iron plateprocessing and the like.

In the field of general industries, examples are a packing, an O ring, ahose, a seal material, a diaphragm, a valve, a roll, a tube, a lining, amandrel, an electric cable, a flexible joint, a belt, a rubber plate, aweather strip, and a roll, a roll blade and a belt for a PPC copyingmachine. Concretely, a seal of a hydrauric, lubricating machine, abearing seal, a seal for a window and other parts of a dry cleaningequipment, a seal for an uranium hexafluoride condenser, a seal (vacuum)valve for a cyclotron, a seal for an automatic packaging machine, adiaphragm for a sulfurious acid gas and chlorine gas analytical pump (apollution finder), a roll, a belt and a roll of an acid cleaningaperture for a printing machine.

In the field of electricity, concretely, examples are an insulating oilcup for a bullet train, a benching seal for a liquid ring trance, and ajacket for an oil well cable.

In the field of fuel batteries, concretely, examples are used forelectrodes, a seal material between or between separators, and a sealfor a hydrogen-oxygen-purified water pipe.

In the field of electric components, concretely, examples are used for amodifier for a print circuit board pre-preg plastic such as an epoxy anda raw material of an electromagnetic waves shield material and ashatterproof material such as a bulb,and a gasket for a hard disc driveof a computer.

Particularly, examples are used for a gasket, a seal material and ahose, an O (square) ring, a tube, a packing, a core material for avalve, a seal material and a diaphragm, which are employed for a fuelsystem of an automobile, due to an excellent fuel oil resistance.

The present invention is explained with examples in the following, butthe present invention is not limited to the examples.

Evaluation Method

<Weight Average Molecule Weight(Mw) and Number Average Molecule Weight(Mn)>

-   Equipment: HLC-8020 (made by TOSOH CORP.)-   Column available from Showa Denko K.K.: GPC KF-806M 2    -   GPC KF-802 1    -   GPC KF-801 2-   Detector: differential refractometer-   Eluent solvent: tetrahydrofurun-   Temperature: 35° C.-   Sample concentration: 0.1 weight %-   Standard sample: various monodisperse polystyrenes ( (Mw/Mn)=1.    14(Max) ), TSK standard POLYSTYRENE (made by TOSOH CORP.)    <Permanent Compression Strain>

The following standard compounds are subjected to primary pressvulcanization and secondary oven vulcanization under the standardvulcanizing conditions to prepare an O ring, and a permanent compressionstain after a primary press vulcanization and a permanent compressionstrain (Cs) after secondary oven vulcanization are measured (measuresamples which are left for 30 minutes in a room at a constanttemperature after holding them for 72 hours at 200° C. under pressuringwith 25% compression) according to JIS-K6262.

(Standard Amount) Polymer 100 parts by weight Triallylisocyanurate(TAIC)4 parts by weight Perhexa25B 1.5 parts by weight Carbon black MT-C 20parts by weight(Standard Vulcanization Conditions)

-   Kneading method: roll kneading-   Press vulcanization: 10 minutes at 160° C.-   Oven vulcanization: 4 hours at 180° C.    <100% modulus (MIOO)>

The standard compound is subjected to primary press vulcanization andsecondary oven vulcanization under the standard vulcanization conditionsto prepare a 2 mm thickness sheet, and the 100% modulus is measuredaccording to JIS-K6251.

<Tensile Strength at Break (Tb) and Tensile Elongation at Break (Eb)>

The standard compound is subjected to primary press vulcanization andsecondary oven vulcanization under the standard vulcanization conditionsto prepare a 2mm thickness sheet, and the tensile strength at break andthe tensile elongation at break are measured according to JIS-K625 1.

<Hardness (Hs)>

The standard compound is subjected to primary press vulcanization andsecondary oven vulcanization under the standard vulcanization conditionsto prepare a 2mm thickness sheet, and the hardness is measured accordingto JIS-K6253.

<Vulcanization Properties>

The vulcanization curve at 170° C. is found in primary pressvulcanization using JSR model curastometer II and V, and the minimumviscosity (ML), the degree of vulcanization (ML), the induction time(T₁₀) and the optimum vulcanization time (T₉₀) are found.

<Chemical Composition Analysis>

The chemical composition analysis was conducted by ¹⁹F-NMR (made byBruker BioSpin K.K. AC300P).

<Elemental Analysis>

CHN CORDER MT-5 made by J-SCIENCE LAB Co.,Ltd. F ion metermicroprocessor ionanalyzer/901 made by Orion Corp. Ltd.

EXAMPLE 1

According to the method described in Japanese Unexamined PatentPublication No. 62-12734, ICH₂CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)COOCH₃ (IFM-1)was synthesized. A stainless autoclave was charged with 58.2 g of IFM-1,600 g of vinylidenefluoride (VdF) and 1500 g of hexafluoropropyleneafter conducting nitrogen substitution, the temperature was maintainedat 25° C., and initiated polymerization by adding 1.6 mL of[Cl(CF₂CFCl)₂CF₂COO—]₂ (DLP) diluted with 20% by weight of F(CF₂)₆F.After reacting for 30 hours, more 1.6 mL of DLP was added, and whenpressure decreased to 1.65 MPa from 1.85 MPa after 66 hours, a gasmonomer was discharged, and the reaction of polymerization was finished.255 g of polymer A in the state of starch syrup was obtained. Thecomposition of polymer A was VdF/HFP=80/20, number average molecularweight was 2500, weight average molecular weight was 4800, and Mw/Mn was1.92, which were measured by GPA and converted with polystylene.

Subsequently, the polymer which was separated into two phases in theearly stage became one uniform phase and the viscosity was increased byagitating 20 g of a liquid silicone rubber DMS-A15 (made by Gelest,Inc., molecular weight 3000, NH₂ concentration of 1.1% by weight)containing an amino group at the end of the polymer and adimethylsiloxane unit and 47 g of the above mentioned polymer A forapproximately one hour at 50° C. An unreacted polymer A was eliminatedby washing this polymer with acetone and 61 g of a block polymer havingrespective segment of a fluorine rubber and a silicone rubber wasobtained.

0.4 g of triallylisocyanate (TAIC: made by Nippon Kasei chemical Co.,Ltd.) and of 0.15 g of perhexa2.5 B (made by NOF Corp.) are mixed with10 g of the obtained fluorine rubber silicone rubber block polymer, andthe hardness behavior was examined by JSR model curastometer. 1.9minutes of the induction time, 3.5 minutes of the optimum vulcanizationtime, 0.0 kgf of the minimum torque, 1.4 kgf of the maximum torque wereread, and a transparent and bistered cured compound was obtained.

EXAMPLE 2

20 g of the fluorine rubber silicone rubber block polymer obtained inExample 1, 90 g of a peroxide-vulcanizable fluorine rubber B (DaielG801, made by Daikin Industries, Ltd.) and 90 g of aperoxide-vulcanizable silicone rubber C (available from DMS-V42 Gelest,Inc.) were dispersed by rolling and a curable composition was obtainedby mixing 8 g of TAIC, 3 g of perhexa 25b and MT carbon (N900, made byCancorb Ltd.). A crosslinked sheet was obtained by heat treating thiscomposition at 180° C. for 4 hours in the oven after press vulcanizationat 160° C. for 15 minutes. Mechanical properties of this crosslinkedsheet were 1.2 MPa of 100% modulus, 5.5 MPa of the tensile strength,480% of the elongation and 65 of the hardness (JIS A).

INDUSTRIAL APPLICABILITY

According to the present invention, a graft or a block polymercomprising at least one kind of a silicone rubber segment and at leastone kind of a fluorine elastomer segment, which is excellent in oilresistance, heat resistance, chemical resistance, how hardness and coldresistance, can be obtained.

1. A graft or a block polymer comprising at least one kind of a siliconerubber segment and at least one kind of fluorine containing elastomersegment.
 2. The graft or the block polymer of claim 1, wherein thefluorine containing elastomer segment is an elastomer segment comprisinga vinylidene fluoride or an elastomer segment comprisingtetrafluoroethylene.
 3. The graft or the block polymer of claim 1,wherein the silicone rubber segment has a unit of dimethylsiloxaneand/or methyl-3,3,3-trifluoropropylsiloxane.
 4. The graft or the blockpolymer of claim 1, which is obtained by reacting a fluorine containingcompound having an fluorine containing elastomer segment obtained bypolymerizing a fluorine containing monomer with the fluorine containingcompound represented by the formula (1):

(wherein X¹ is an iodine atom or a bromine atom, R_(f) ¹ is a bivalentalkylene group having 1 to 30 carbon atoms and possibly containing anoxygen atom, R¹ is an alkyl group having 1 to 3 carbon atoms), with asilicone rubber having at least one amino group.
 5. A curablecomposition comprising the polymer of claim 1, and a vulcanizing agent.